Towards a Scalable Content-Based Publish/Subscribe Service over DHT

Content-based publish/subscribe allows for highly expressive descriptions of subscriptions and thus is more appropriate for content dissemination when a finer level of granularity is necessary. However, scalability has become an issue due to the expensive matching and delivering inherent in content-based events. In this paper we propose a novel content-based publish/subscribe framework built over DHT-based P2P network in order to provide a scalable pub/sub service. There are three key features in our design: (1) Domain space mapping and distributed 2d-tree over DHT; (2) Novel random probing search algorithms developed for subscription installation and event publication; (3) Efficient application layer multicast algorithm and load balancing scheme to scale the system.